Abstract

Surface modification is the act of modifying the surface of a material by generating physical, chemical or biological characteristics different from the ones originally found. A common way to achieve this goal is through chemical functionalization, which consists in introducing new functional groups on the surface of the “substrate” material. Besides increasing the chemical reactivity of the surface, these new chemical groups need to be carefully chosen to match the surface groups or molecules of a second material which the substrate is aimed to interact with, promoting physico-chemical interactions. For the case of carbon nanotubes (CNTs), their strong C-C covalent bonding and ring structure render excellent physical properties, but also renders low chemical reactivity which difficults their interaction with polymer molecules. This has motivated the need of chemical (and physical) surface modifications on CNTs with the aim of improving physic-chemical interactions with host polymers. The selection of the CNT functionalization method and molecule(s) used strongly depends on the chemical nature of the host polymer, and their selection is a topic addressed in this Chapter. Although the mechanical properties of CNT/polymer composites may not compete with those of fiber-reinforced polymer composites, the selection of an adequate CNT functionalization method/bridging molecule could greatly assist in creating proper interfaces for improved mechanical, thermal, electrical and multifunctional properties of polymer nanocomposites.